When I first received pxl SmartScale, I thought it was a fancy-dancy algorithm to create pixels when expanding the size of images. Boy was I wrong--it's much more than that. Some are likely to hail the advances of what pxl SmartScale can do while others just may not like it for the same reasons. Regardless how you may like the results, all Photoshop Users must appreciate what Extensis has created.

But first some background: all digital images are created with pixels and there are two truths to pixels. Pixels are square (except for video pixels) and pixels can only be one color (hue/shade/intensity). When you take an image that is (say) 730 x 541 pixels and blow it up to (say) 2924 x 2164 (a 400% expansion in size), a total of 6,327,043 pixels had be created/invented by the software to fill in the gaps.

Please keep that in mind when watching some cop/FBI/CIA show when the investigator asks the Photoshop techi person to zoom into an image to get a better view of the guilty party and low and behold, it's Brad Pitt as clear as day. All one can do when one wishes an image to become larger is to take the available information in the image and for the software to create the best guess when increasing the pixels. Thus, all the Photoshop techi person can do is to take a small non-discript image and turn it into a larger non-discript image. This process is called resampling and in Photoshop is done by going into the Image (menu) -> Image Size... selection and place a larger percent or number of pixels in the width or height of the image with the bottom selection of "Resample" checked on.

Now the reason why someone might want to do this is typically the image they have does not have enough pixels to create a print large enough for their needs. This can be either because their camera does not have enough megapixels and/or after cropping an image there are not enough pixels left to create a sufficiently large print. I occasionally have both problems.

My camera is only a 1.3 Megapixel camera. It's the Olympus 100RS. I love it because of it's rapid shoot features and its 10x optical zoom. For taking images for the web, it's great because most web images are only 500-600 pixels wide maximum, well within the 1360 pixels maximum width my camera's images. But if I need to crop and image and wish for a large print, I'm screwed.

Below is an image of a dragonfly that's 1360 x 1024. [The image below is significantly decreased in size and matched up with the cropped image so the reader can compare the relative image size before and after cropping.] I ended up cropping that image down to 731 x 541. If I wanted to print at 300 dpi, the image size would only 2.44 x 1.8 inches. If I want to print the image 4 times that size, I would need 16 times the number of pixels?

There are several ways to do such expansion of an image. The easiest way is to go into the Image Size... dialog box and increase the size of the image with the Bicubic option selected. It does do a good job. In addition, in the past there have been several creative ways to try and improve the quality of the image. One of the more creative was by using Stair Interpolation. The idea here was if you wanted to increase the size of your image 4 times, it was not realistic to expect software to create that many pixels out of thin air all in one fell swoop. So, what if you created an Action that did it 10% at a time. This would let Photoshop sneak up on the desired size with hopefully fewer mistakes. So, someone created an Action that let the user select from subset sizes of 1.5x, 2x or 4x and let Photoshop's Action do the rest. It seems logical and obvious, but I've never seen a significant level of improved quality to warrant Stair Interpolation--perhaps by the time I got involved with Photoshop, Photoshop's own resampling was more than good enough to not find any benefit with the Stair Interpolation approach.

To test pxl SmartScale, I felt that this dragonfly had two very important features, sharp lines and smooth areas. The reason for this is very important because of the way that pxl SmartScale works: As I'm sure you know, there are two kinds of digital images--vector images and bitmapped images.

Vector images are those created by programs like Freehand and Illustrator. With these, a line is not a collection of pixels, but rather two points and the computer fills the region between those two points with pixels. The size or length of the two points can be varied at any time and at any magnification because the computer will fill the region between those two points on the fly at any time.

Bit mapped images are those like photographic images where a line is a collection of pixels creating a line. If you zoom in, you just see a closer image of those pixels.

What pxl SmartScale does is to take a very close look at your image and look for lines. A line is any continuous variation between shades, hues, or intensity. A profile is a good example of a bitmapped image "line." Photoshop is already good at finding lines in bitmapped images. If you go to Filter -> Stylize -> Find Edges, you can create images like this:

What pxl SmartScale does is to find the edges, create vector lines for those bitmapped lines, re-scales the images and creates a better selection of created pixels to fill that space than can be done by Bicubic sampling. Using this technology, images can be increased in size 1600% with no pixellation.

To use pxl SmartScale is very easy. You select pxl SmartScale from the Extensis menu (added to Photoshop with any Extensis plugin instillation and select either the current image or one from a file. Once opened, you select the final size by either sliding the scale triangle or by typing in the desired final width or height for the image or document size. There are a variety of choices that can be made with the desired final detail.

Below is the wing of the dragon fly blown up 400% and seen at 100%. On the left is the result using Photoshop's Image Resize (using Bicubic resampling), and on the right is the same image but using the Step Interpolation technique. The main difference I can see is that the latter provides darker darks and lighter lights, and there is less separation between the superstructure of the wing.

Below here is the same image but using pxl SmartScale. On the left is the image at 400% seen at 100%, and on the right the image is blown up to 800% but seen at 50%. Among the differences seen from the images above is the wing structure is much sharper and the image itself has less noise. [This makes sense because noise would not create a line and therefore would be ignored during the size increasing process.] The differences between the two below seems to be the built-in sharpening of the image shows a greater halo with the 8x than the 4x.

But, as mentioned, what about parts of the images that do not have clear defined lines--the head to be exact.

Below is the head, again blown up 400% and seen at 100%. On the left is the result using Photoshop's Image Resize (using Bicubic resampling), and on the right is the same image but using the Step Interpolation technique. Just like the wings, nothing to write home about. But there is a significant amount of texture in the image.

save: psd 30.9 MB	saved: tif 11.8 MB	saved: vfz-5 21.2 MB	saved: vfz-4 14.8 MB

save: vfz-3 9.9 MB	saved: vfz-2 6.2 MB	saved: vfz-1 3.5 MB	saved: vfz-0 1.6 MB

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